Meter mounting box

ABSTRACT

A meter mounting device has a pair of jaw terminals for accepting terminal tongues of a meter with a bell crank lever pivotally mounted on one jaw terminal. One part of the lever extends beyond the jaw terminals in position to be engaged by the meter when the meter is put in place. A bridging bar is secured to the lever. There is a contact surface on each jaw terminal, such surfaces being positioned such that the bar will bridge them when the meter is removed and absent.

United S-tates Patent [111 3,869,188 Morrison et al. 9' l Mar.4, 1975 i 1 METER'MOUNTING BOX 2,747,050 5/1956 Johansson 339/198M [75] lnvemorszlan Y. Morrison, Ml-s'sinaug& 7 3,587,423 6/1971 Simon 339/95 R Ontario; London C. Spark, I Newmarket, Ontario; Jeue J. Duyf, Primary E.\'ammerJoseph H. McGlynn Toronto Ontario all of Canada Attorney, Agent, or FirmDavis, Hoxie, Faithfull & Ha 00d [73] Assign-6e: Murray-Jensen Manufacturing pg Ltd., Toronto, Ontario, Canada [22] Filed: Mar. 26,.1973 I [57] ABSTRACT [II I Appl. No: 344,530 A meter mounting device has a pair of jaw terminals t r -m Appmmiun p m for accepting terminal tongues of a meter with a bell I crank lever pivotully mounted on one jaw terminal. 197': 138462 One part of the lever extends beyond the-jaw termi- 52 ,5, 1 339 95. 317 07, 339 193 M nals in position to be engaged by the meter when the 511 int. CL H0lr 13/38 meter is p in place. A ging bar is secured to the {53] Fi ld f S h 339/95, 193; 317/107 lever. There is a contact surface on each jaw terminal, such surfaces being positioned such that the bar will [56] References Cit d bridge'them when the meter is removed and absent.

UNITED STATES PATENTS v I 2,217,433 10 1940 Crabbs 339 95 R 3 Claims, 4 Drawing Figures I5 25 I 7 II In il L g l llh. ll L 1 METER MOUNTING BOX -meter, commonly called a'meter mounting, having jaw terminals for receiving the contact blades of a detachablemeter and a conductive bar for bridging the line and load terminals when the meter is removed from the jaw terminals.

Known meter mounting boxes include those shown in the following Canadian Patent Nos:

503,652 issued June 15, 1954 to Anchor Manufacturing Company;

557,881 issued May 27, l958to Anchor Manufacturing Company (corresponding US. Pat. No. 2,747,049);

645,941 issued July 31, 1962 to Basic Products Corporation;

645,942 issued July 31, 1962 to Basic-Products Corporation.

All of the apparatus disclosed in the above-noted patents show a'bar for bridging line and load terminals in is operated by a plunger which contacts it and moves the bar normal to a contact surface beneath one of the jaw terminals. '7 Sparking when, making or breaking contact by retracting or inserting a meter into the jaw terminals, is inevitable, however, with all of the prior art apparatusdeposit buildup through sparking which occurs between the bridging bar and the contact surface beneath one of the jawterminals is permitted to remain in place until overhaul and, hence, poor contact is obtained for most of the operating life of the apparatus.

The apparatus of this invention, however, is a meter mounting box having jaw terminals and a bridging bar movable away from and towards contact surfaces beneath the jaw terminals. The bridging bar is pivoted to a bell crank lever, one arm of the bell crank lever protruding past the jaw terminals such that the bell crank lever will be rotated when a meter is moved towards and away from the jaw terminals. The bridging bar, through its position of connection to the bell crank lever, moves upon the arc of a circle and the ends of the bridging bar are forced to slide along the contact surfaces beneath the jaw terminals so wiping and cleaning the build-up, caused by sparking from the bar and the Contact surfaces. The bar and the contact surfaces are, therefore, self-cleaning.

The invention will now be described with reference to the accompanying drawings in which: 7

FIG. 1 is a plan view of one embodiment of the mounting box of this invention;

seen in FIGS. 2 and 3, a flexible jaw piece 7 'is riveted or connected to and faces each flange 13a. Each jaw terminal has a metallic stud 11 mounted in a right angle stamping and a metal clamp 12 for gripping electrical wires (not shown).

Between each pair ofjaw terminals there is a triangularly-shap'ed bell crank lever 25 having an upwardly extending arm 17. A pivot pin 19 extends through an aperture in long flange 13a of each pair ofjaw members, and through one extremity or corner 15 of the bell crank lever 25 and also through a coiled hairpin spring 21 which is wound around pin 19. One end of the spring engages the edge of arm 25 while the other end engages the edge of transverse part 13b of the terminal member 13. The lever 25 has a downward projection 29 from one side edge with a hole for accepting a locking pin 31. A bridging bar 33 is situated between each pair ofjaw terminals 13, each bar having contact ends 35 and 37 which can respectively contact the outer or lower surfaces (as .viewed in FIGS. 2 and 4) of the transverse portions 13b of the facing pairs ofjaw terminal members. The bridging bar 33 has a flat edged aperture such as a square aperture in its central region through which projection 29 can pass. After the bridging bar is assembled on the projection 29 the locking pin 31 is inserted transversely through the extension outside the bar 33, so that when pin 31 is in place, the bridging bar 33 is secured non-rigidly on the bell crank lever 25, as is usual when a bridging bar must accommodate itself to the positioning of the fixed contacts.

Insulation plates 39 are positioned between adjacent pairs of the jaw terminal members and are each secured in place with a tab 41 which passes through a slot 43 in the base 1. A locking pin 45 is passed through an aperture in each tab 41 to hold the insulating plates 39 in place.

During operation of the apparatus, as a meter is connected across a pair of jaw terminal members, the contact blades of the meter are inserted in the jaw terminals. Concomitantly, the associated bell crank lever 25 is rotated clockwise, looking at FIG. 2, by the meter which contacts arm 17.

The rotation of the lever 25 carries the bridging bar 33'with it bodily in a segment of an orbit, the center of which is the .axis of the pivot pin 19. Sincethe end portion 35 of the bar 33 is nearer to the pin than the end portion 37, the curvature of the arcs of movement of said end portions are different. They will nevertheless engage and disengage the contact surfaces on the outer surfaces of the transverse portions 13b of the terminal members 13, at approximately the same time. It will be FIG. 2 is a side elevational view of the mounting box of FIG. 1';

' left U-shaped jaw terminal members designated generally by 13, are secured to the upper ends of the posts 5 by bolts 9 Each jaw terminal member has a pair of projecting flanges 13a, 13c, respectively, extending perpendicularly to a transverse connecting portion 13b. As may be recalled, however, that the bridging bar is not rigidly mounted on the extension 27 of the member 25 but is loosely maintained in place thereon by pin 31. In consequence of this and of the difference in the curvature of the arcs of movement of the end portions 35 and 37,

there is a rubbing or slight sliding action of the contact portions 35 and 37 over the respective fixed contact surfaces with which they engage and disengage.

When removing the meter, spring 21 forces the bell crank lever 15 to rotate anti-clockwise and the contacts 35 and 37 are moved into engagement with the contact surfaces on the terminal members 13. The movement is again one incorporating a sliding action between the contacts 35 and 37 and their respective contact surfaces on the terminal members 13. Any deposi'tbuildup due to sparking or any cause such as dirt, dust,

and wiped-off by the sliding. action.-

It is thus seen thatthis apparatus provides a novel mechanism to-achieve self-cleaning of contacts in a meter-mounting box.

We-Claim:

l. lnameter mountingdevice havinga pair of jaw terminals for accepting terminal tongues of a meter whenthe meter is mounted; a lever pivotally mounted on one jaw terminal, said lever having a portion extending into position to be engaged by a meter when its tongues are accepted in said jaw terminals; a bridging bar mounted on'and secured to said lever; and a contact surface on each jaw terminal, said contactsurfaces being positioned to be engaged and bridged by said bar when said meter is absent, and said bridging bar being positioned toslidingly engage and disengage said contact surfaces as-said meter is mounted and removed, thereby-cleaning the contact surfaces; and a spring mounted at the pivotedend of said lever and presses against one of said jaw terminals and against said lever to bias said lever and bar into bridging position, i

2. A device as claimed in claim 1 wherein said portion of said lever is an arm extending beyond said jaw lever has a projection which passes through said aperture; and a locking pin which extends through said projection to hold said bar onto said lever. 

1. In a meter mounting device having a pair of jaw terminals for accepting terminal tongues of a meter when the meter is mounted; a lever pivotally mounted on one jaw terminal, said lever having a portion extending into position to be engaged by a meter when its tongues are accepted in said jaw terminals; a bridging bar mounted on and secured to said lever; and a contact surface on each jaw terminal, said contact surfaces being positioned to be engaged and bridged by said bar when said meter is absent, and said bridging bar being positioned to slidingly engage and disengage said contact surfaces as said meter is mounted and removed, thereby cleaning the contact surfaces; and a spring mounted at the pivoted end of said lever and presses against one of said jaw terminals and against said lever to bias said lever and bar into bridging position.
 2. A device as claimed in claim 1 wherein said portion of said lever is an arm extending beyond said jaw terminals in position to be engaged by the meter, and said bar moves in an arcuate path to accomplish said wiping action.
 3. The device of claim 2, wherein said bridging bar has an aperture through its central region, and said lever has a projection which passes through said aperture; and a locking pin which extends through said projection to hold said bar onto said lever. 